The 27-meter double-decker tourist ship 'Hableány' (Mermaid) was on a tourist cruise on Danube with a total of 35 people onboard, when it collided with the 135-meter luxury cruiser 'Viking Sigyn' and sank quickly. Only seven people were rescued. The 33 out of the 35 onboard at the time were South Korean nationals.

Video by Hungarian police shows the big cruise vessel, 'Viking Sigyn' crashing into the smaller one.

Shortly after, the Hungarian court ordered arrest of the 64-year-old Ukrainian captain of the cruise vessel for a month, with the possibility of a $50,000 bail for his release.

Yet, the prosecutors denied the possibility of bail, so the captain will remain behind bars until the court rules on the appeal in the next weeks.

The Captain refuses accusations, saying he has done nothing wrong.

Authorities would start trying to secure the vessel to prevent the loss of bodies and prepare for a possible salvage, South Korean defense attache Song Shun-keun told journalists in Budapest.

The vessel is to be raised later this week, because flood waters has made it impossible for the rescuers to reach the submerged boat so far.

It is still unclear what caused the incident.